油藏条件下泡沫油的油气相渗规律研究

委内瑞拉Orinoco地层油除了具有常规稠油的基本特性外,随开采压力的变化还呈现出极为复杂的“泡沫流体”流动特征,是典型的非牛顿流体,在油藏中的渗流过程属于非达西渗流,其在油藏条件下的油气相对渗透率关系还不清楚.长岩心衰竭实验显示了泡沫油的开发特征,缓慢的采油速度可使油气两相保持稳定.对常规油气相渗非稳态方法进行改进,利用气体驱替的慢速开发实验,结合衰竭实验和PVT实验的数据,计算出高温高压状态下泡沫油的油气相对渗透率关系.该方法对油气体积进行了准确的校正,计算的油气相渗关系显示出泡沫油的独特性:含气饱和度很低;气相相对渗透率值很低;油气两相曲线没有交点,在测试结束点时,气相相对渗透率值会迅速增长.

Study on foam oil and gas relative permeability under reservoir conditions

In addition to the characteristics of normal heavy oil,the oil in Orinoco,Venezuela has the complex flow performances of foam fluid It is a kind of typical non-Newtonian fluid,and its seepage in reservoir is non-Darcy flow.The pressure depletion experiment in long core model is carried out in order to understand the oil and gas relative permeability characteristic of the foam oil under reservoir conditions.The experiment shows that less oil production rate can make the oil and gas phases of the foam oil keep steady.The general unsteady experimental method is improved;together with the pressure depletion and PVT experimental data,the oil and gas relative permeability characteristic of the foam oil under high-temperature and high-pressure is obtained from the gas flooding experiment at low production rate.A more accurate volumes of oil and gas can be obtained using the new experimental method,and the calculation results show that the foam oil has low gas saturation,its gas relative permeability is low,there is no intersection of oil and gas relative permeability curves,and the gas relative permeability rapidly increases near the end of test.